1. Field of the Invention
The present invention relates to a floating data interface, particularly for monolithic integrated circuits.
2. Description of the Related Art
There are many applications in which data has to be read on a floating basis. For example, if data lines are long and faulty, the potential variations between data source and data sink may be too large, so that the data will not be correctly recognized or the associated circuits will be destroyed by voltage spikes. A certain remedy is provided by transmitting the data as difference signals over a two-wire line and evaluating them by means of a differential input stage, which, as is well known, can suppress DC level variations provided that the variations lie within the permissible dynamic range. Another known remedial measure is the use of optocouplers, which are inserted as a floating data interface between the respective circuit and the data bus. This, however, is expensive and requires additional circuitry.
It is, therefore, the object of the invention to provide a floating data interface which is especially suitable for monolithic integrated circuits and can be implemented together with the latter on a single chip.